Routine Therapy Plus Moxifloxacin in Advanced Breast Cancer

Inclusion Criteria:

* Female ≥ 18 years, ≤70 years.
* Has measurable metastatic MBC, with at least 1 measurable lesion per RECIST criteria.
* Fail first-line or above anti-tumor treatment
* Evaluation is stable disease with a trend of progression.
* Minimum life expectancy 16 weeks
* Histological confirmation of breast cancer on primary tumour at diagnosis/on biopsy of metastasis
* ECOG Performance Status (PS) 0-2 with no deterioration over previous 2 weeks
* Normal organ function.
* Has signed a Patient Informed Consent Form

Exclusion Criteria:

* Hypersensitivity to moxifloxacin or other quinolones.
* Tendon damage,peripheral neuropathy,myasthenia gravis.
* Rapidly progressive visceral disease not suitable for further therapy.
* Evidence of severe or uncontrolled systemic diseases, including uncontrolled hypertension, active bleeding diatheses, or active infection including hepatitis B, hepatitis C and HIV
* With the exception of alopecia, any unresolved toxicities from previous therapy greater than CTCAE grade 1 before study treatment
* Evidence of dementia, altered mental status or any psychiatric condition that would prohibit understanding or rendering of informed consent
* Inability or unwillingness to comply with study procedures, including inability to take regular oral medication
* Researchers consider it is not suitable for participation.